In my hang gliding club we have members who go back to the beginnings of the sport. Although we have many young pilots in their early 20s, the average age of our pilots is probably around late 40s to 50, with our oldest still flying at 83. Back in the early 70's, these guys would build gliders out of plastic sheeting, PVC pipe, and rope, all duct-taped together, and then tie themselves to it and jump off mountains and fly thousands of feet above the ground with no parachute. None would ever think of doing that today.

It's amazing what can be made to fly and how easy it actually is for a human to fly un-powered with simple materials. When you see how easy it is now, it's hard to believe it took thousands of years to realize man's most universal and passionate dream. It turns out that technology had very little to do with it. Maybe it was all in the weed.